The invention relates to an energy storage arrangement for supplying electric power, in particular in a motor vehicle. The energy storage arranagement is composed of at least two energy storage modules. In each energy storage module, a plurality of storage cells are braced against one another between two end plates.
In a device for supplying electric power in a motor vehicle, usually characterized as a battery, a plurality of energy storage modules are generally used to drive the vehicle, for example in electric vehicles or hybrid vehicles. Each energy storage module typically includes a plurality of stacked prismatic storage cells. The individual storage cells contain electrochemical cells of the battery. In most cases, the stack of individual storage cells is tensioned (braced) by use of a mechanical end plate and a tie bar to form the energy storage module. In addition to mechanically securing the modules relative to one another, the end plates and tie bar serve, in particular, to counteract any deformation resulting from changes in gas pressure in the electrochemical cells arranged inside the modules that may occur during operation.
The object of the present invention is to provide an energy storage assembly in which a plurality of energy storage modules are combined in a weight-optimized, reliable and crash-proof manner in a cost-efficient production and assembly process.
This and other objects are achieved by an energy storage arrangement for supplying electric power, in particular in a motor vehicle, said arangement having at least a first energy storage module and a second energy storage module which is mounted on top of the first energy storage module. Each of the energy storage modules has two end plates and a plurality of storage cells tensioned between the end plates. The storage cells are generally embodied as prismatic and are stacked in series in the energy storage module. Thus, an energy storage module may comprise a single row of storage cells or a plurality of parallel rows of storage cells. The individual storage cells, in turn, comprise a plurality of electrochemical cells. The energy storage modules are secured by way of screws. The screws are inserted through the end plates. The screws used for securing a first, lower energy storage module are identified as “first screws”. The second energy storage module, mounted on top of the first, is secured by “second screws”.
According to the invention, an internal thread is formed in the screw heads of the first screws. The second screws are screwed into the internal thread in the screw heads of the first screws. Thus, according to the invention, the end plates of the upper energy storage module can be attached directly to the end plates of the lower energy storage module. In this process, the upper energy storage module is screw-connected to the screw heads of the first screws.
According to the invention, no supporting intermediate bases are necessary between the energy storage modules, and no special structures are required in the housing in order to attach the second energy storage module. The result is a cost-effective, assembly-optimized and weight-optimized configuration of the energy storage arrangement, particularly for a motor vehicle. The energy storage arrangement is used, in particular, for exclusive or for auxiliary driving of the motor vehicle. The term “motor vehicle” includes automobiles, trucks, forklifts, etc.
More than two energy storage modules are preferably arranged one on top of the other, in which case one energy storage module is screw-connected to the screw heads of the energy storage module beneath it.
Particularly preferably, each end plate is secured by at least two screws. The end plates of the bottommost energy storage module (first energy storage module) are preferably screw-connected to a housing or a supporting structure.
It is further preferably provided that an inner polygon is formed in the screw head of the first screw. This inner polygon is arranged coaxially to the internal thread in the screw head. The first screw can be tightened via the inner polygon using an appropriate tool.
It is further preferably provided that the first screw comprises a shoulder. The shoulder rests on one of the end plates of the first energy storage module. One end plate of the second energy storage module rests on the screw head of the first screw. In particular, the first screw comprises a lower region, which has an external thread, and an intermediate region between the lower region and the screw head. The external diameter of the screw head is preferably greater than that of the intermediate region and the lower region. As a result, the above-mentioned shoulder is formed at the transition point between screw head and intermediate region.
It is further preferably provided that an intermediate base is arranged between the first energy storage module and the second energy storage module. This intermediate base does not serve as the sole supporting structure for the second energy storage module. The intermediate base is used for supporting a cooling device, for example. The cooling device is mounted on the intermediate base and serves to cool the second energy storage module. Moreover, the intermediate base can be used as a simple insulation element between the two energy storage modules. The intermediate base is preferably clamped between the screw head of the first screw and one of the end plates of the second energy storage module. The intermediate base is preferably also used for supporting the energy storage modules on the housing and therefore for stabilizing the energy storage assembly.
In the preferred embodiment, the first screws and the second screws are identical, allowing the number of shared components used to be maximized. In that case, the internal thread formed in the screw head of the second screw remains unused.
The end plates of the energy storage modules preferably comprise vertical through holes, into which the first and/or second screws are inserted. These through holes preferably span the entire height of the end plates, so that the entire length of the first and/or second screws is accommodated within the end plates.
The invention further comprises an energy storage arrangement for supplying electric power, in particular in a motor vehicle, having at least one energy storage module and a component mounted on the first energy storage module. The energy storage module comprises two end plates and a plurality of storage cells tensioned between the end plates. At least one end plate of the energy storage module is secured by way of at least one first screw, and the component is secured by at least one second screw, wherein an internal thread is formed in the screw head of the first screw, and the second screw is screwed into the screw head of the first screw. The component to be secured is preferably a cover, a protection box or a control unit. The screws are embodied similarly to the stacking of the energy storage modules.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.